Properties of Magnesium Strips Produced by Twin-Roll-Casting and Hot Rolling

Abstract

The combination of Twin-Roll-Casting (TRC) and subsequent rolling constitutes the most promising process chain for producing magnesium strips economically. Fast solidification (10 times faster than continuous casting) combined with partial deformation lead to a fine primary microstructure as well as less shrinking holes, pores, segregations and brittle precipitations which all together has a very positive effect on forming behavior of the initial material and quality of the final product. The paper elaborates on metallurgical processes in consideration of microstructure and texture results and on the obtained mechanical properties of TRC magnesium strips and finished strips. In addition, the influence of twin-roll-cast and rolling conditions on the mechanical properties will be discussed. The investigation has also been expanded to possible heat treatments and their influence. Concluding remarks will be made on results of rolling trail which were carried out on an industrial scale rolling mill, revealing that the production of hot rolled thin sheets of magnesium alloy AZ31 is possible with a very promising combination of strength and ductility.

Deformation Behavior and Fatigue Analysis of Magnesium Wrought Alloys under Variable Amplitude Loading

“…The average grain size in all spatial directions is about 5 μm and the sheet metal reveals a strong basal texture [9]. Further information about the manufacturing process is given by Kawalla et al [3]. The deformation as well as the fatigue behavior of AM50 at constant amplitude loading is investigated in [9].…”

“…Magnesium sheet metals reveal a hexagonal close packed crystal structure with a strong basal texture (e.g. [3,4]), which is responsible for an asymmetrical and anisotropic deformation behavior. The reason for the tension-compression asymmetry is the direction dependancy of {10-12}<10-11> extension twinning [4].…”

“…For a supply with thin magnesium sheet metals, an economical twin roll strip casting process was recently developed (e.g. [3]). Magnesium sheet metals reveal a hexagonal close packed crystal structure with a strong basal texture (e.g.…”

A Comparative Study on the Hot Deformation Behavior of As-Cast and Twin-Roll Cast Mg-6.8Y-2.5Zn-0.4Zr Alloy

“…In addition to the more economical and resource-saving production by reducing the forming and annealing effort during TRC, the quality of the cast strips can basically be improved in terms of homogeneity. The cooling rates (up to 2 106 K/s according to Allen et al (2001) [14], i.e., about ten times faster than in slab casting), which depend on the strip thickness, have a positive effect on the microstructure and macrostructure of the strip during solidification, as well as on the precipitation state [15]. A transfer of the hot deformation behavior from the as-cast condition to the TRC condition is only possible to a limited extent, due to the microstructural differences.…”

Superplastic forming ability of as‐cast AZ91 Mg alloy prepared by twin roll casting

“…Alternative proves of twin roll strip casting (TRC) could reduce the cost and simplify manufacture to the extent that the cost of Mg alloy sheet would be no more than 20% higher than that for Al alloy sheet . POSCO in Korea and Magnesium Flachprodukte GmbH in Germany run two industrial scale twin roll strip casting facilities ready to manufacture 1,500 mm wide Mg coils with reduced costs compared to conventional route .…”